1. Technical Field
The present invention relates generally to wireless communication systems; and more particularly to the equalization of data communications by a wireless radio in a wireless communication system.
2. Related Art
Cellular wireless communication systems support wireless communication services in many populated areas of the world. Cellular wireless communication systems include a “network infrastructure” that wirelessly communicates with wireless terminals within a respective service coverage area. The network infrastructure typically includes a plurality of base stations dispersed throughout the service coverage area, each of which supports wireless communications within a respective cell (or set of sectors). The base stations couple to base station controllers (BSCs), with each BSC serving a plurality of base stations. Each BSC couples to a mobile switching center (MSC). Each BSC also typically directly or indirectly couples to the Internet.
In operation, each base station communicates with a plurality of wireless terminals operating in its serviced cell/sectors. A BSC coupled to the base station routes voice communications between the MSC and the serving base station. The MSC routes the voice communication to another MSC or to the PSTN. BSCs route data communications between a servicing base station and a packet data network that may include or couple to the Internet. Transmissions from base stations to wireless terminals are referred to as “forward link” transmissions while transmissions from wireless terminals to base stations are referred to as “reverse link” transmissions. The volume of data transmitted on the forward link typically exceeds the volume of data transmitted on the reverse link. Such is the case because data users typically issue commands to request data from data sources, e.g., web servers, and the web servers provide the data to the wireless terminals.
Wireless links between base stations and their serviced wireless terminals typically operate according to one (or more) of a plurality of operating standards. These operating standards define the manner in which the wireless link may be allocated, setup, serviced, and torn down. Popular currently employed cellular standards include the Global System for Mobile telecommunications (GSM) standards, the North American Code Division Multiple Access (CDMA) standards, and the North American Time Division Multiple Access (TDMA) standards, among others. These operating standards support both voice communications and data communications. More recently introduced operating standards include the Universal Mobile Telecommunications Services (UMTS)/Wideband CDMA (WCDMA) standards. The UMTS/WCDMA standards employ CDMA principles and support high throughput, both voice and data.
The wireless link between a base station and a serviced wireless terminal is referred to as a “channel.” The channel distorts and adds noise to wireless transmissions serviced by the channel. “Channel equalization” is a process employed by a wireless receiver, e.g., wireless terminal, in an attempt to obviate the effects of the channel. While channel equalization is certainly helpful in obviating the effects of the channel, the characteristics of the channel are constantly changing. Thus, coefficients of a channel equalizer must be continually updated. However, generating coefficients of the channel equalizer is a difficult and time consuming process. Further, equalizer coefficients determined may not be well matched for current channel conditions due to a fixed length of the equalizer and of the changing channel conditions. Thus, a need exists for an improved methodology for determining equalizer coefficients.